Acrolein/glutaraldehyde as a fixative for combined light and electron microscopic immunocytochemical detection of pituitary hormones in immersion-fixed tissue.

In an attempt to find a fixative that has a wide range of application in immunocytochemical studies of pituitary tissue, we have investigated the use of acrolein fixation followed by postfixation in osmium. Pituitary glands were excised and immersion-fixed in 2 or 5% acrolein/0.25% glutaraldehyde for 1, 2.5, 5, or 24 hr. Some tissues were subsequently postfixed in 1% OsO4 for 1.5 hr before embedding in Epon-Araldite. Sections were collected for both light and electron microscopic immunocytochemistry, employing several pituitary hormone antisera. Fixation for 2.5 hr with 2% acrolein/0.25% glutaraldehyde followed by osmication resulted in good staining for both light and electron microscopy with all antisera employed. Furthermore, the rapid penetration qualities of this fixative resulted in good ultrastructural preservation throughout the tissue.